Internal-combustion engine.



No. 866,069. I PATENTED SEPT. 17, 1907. A. ROLLASON. INTERNAL COMBUSTION ENGINE.

APPLICATION FILED SEPT.26. 1905.

2 SHEETS-SHEET l.

I l I l l u l 1 l l l 4 l t "i V INVENTOR No. 866,069. PATENTED SEPT. 17, 1907. A. ROLLASON.

INTERNAL COMBUSTION ENGINE.

APPLICATION FILED SEPT-.26, 1905. v

2 SHEETS-SHEET z.

INVENTOR WWW 4" Maia .is a specification.

ARTH R ROLLASON, or LONG EATON, ENGLAND.

INTERNAL-COMBUSTION ENGINE. A

Specification of Letters Patent.

Patented Sept. 17, 1907.

i 7 Application filed September 26, 1 905. Serial No. 280,116-

To all whom it may concern:

Be it known that I', ARTHUR ROLLASON, a subject of the King of Great Britain, residing at Long Eaton, in the county of Derby, England, engineer, have invented certain new and useful Improvements in or Relating to Internal-Combustion Engines, of which the following This invention relates to improvements in or relat-' ing to internal combustion engines of the Otto or four stroke cycle type which have for their object an increased economy and efficiency of working of such ongines by preventing premature ignition of the charge and increasing the volume of the charge admitted to the cylinder before compression, by effective scavenging of the combustion products, and when applied to tandem engines by providing an elastic cushion which prevents knocking at the end of. the outward stroke and by its elastic reaction accelerates the beginning of the return stroke. The means by which these results are obtained are hereinafter described with reference to an internal combustion engine of the tandem type working on the Otto cycle and are illustrated in the accompanying drawings in which r Figure 1 is a central vertical longitudinal section, Fig. 2 is a sectional plan and Figs. 3 and 4 transverse sections, as on lines 3-3 4-4respectively of Fig. 1,

showing the application of the present invention to an engine of this type.

The cylinders being worked on the four stroke cycle there will be one explosion on eachforward stroke, the explosions occurring alternately in the two cylinders. The valves governing the admission of the charge and the exhaust of the combustion products may be of any suitable known type and may be operated in the usual. manner by cam-actuated tappets or it may be in some cases by the difference of pressure on their two sides, and consequently the precise character of the valves and the means of operating are not herein specifically .referred to or described, as forming no part of the presthe drawings, secured on the rod of the piston b of the motor cylinder 11, forming a guide for the piston, and is connected with the cross-head of the piston b of cylinder a by side rods 6 passing through stuffing boxes in the cover of the cylinder.

The large air cylinder 0 has two ports or sets of ports, one of which f is at the rear of the said cylinder and is in direct communication with the passage g leading to the 'airadmission valves h h of the two motor cylinders .and with the atmosphere through the valve 70, while the other port or series of ports 'i is situated in the cylinderwall at a suitable place intermediate of its ends and communicates through a valve Zwith an air receiver p surrounding the-cylinder c. The time of opening of the ports or series of ports a establishingconununica tion between the, cylinder 0 and the receiver p is controlled by the movement of the plunger d.

The various valves are actuated in proper sequence by suitablemeans to produce the following effects. Assumingthat in the position of the parts shown in the drawings, the combustion chamber m of the cylinder a contains a charge of combustible mixture ready for ignition and that the combustion chamber m of the cylinder a contains the remains of the scavenging. charge of air delivered to it in the manner subsequently explained, when ignition of the charge in chamber m occurs and the pistons are impelled forwards, air is drawn through the valve k, passage g and air admission valve 12 into the cylinder a, and also through the port f into the air cylinder 0 in the rear of the plunger d, while the air in front of the plunger is forced through the ports 2' into the air'receiver p until the ports '5 are covered by the plunger in its forward'movement. The ports 1 remain so covered until near the end of the forward stroke,

when the compressed air in the receiver 1) is admitted to the cylinder 0 in the rear of the plunger 01. The air remaining in front of the plunger after the closing of the ports 11 being compressed by the forward movement of the plunger, is utilized to bring the reciprocating parts to rest and by reoxpansion on the return stroke to accelerate the return of these parts. A supply of air is drawn through valve l, receiver p, ports 1', into-the cylinder c, after the plunger d passes the ports i on the return stroke. During the suction stroke the piston b has drawn a combustible charge through the air admission valve h and gas inlet valve n, these two valves being operated in conjunction in a known manner during the suction stroke so as to admit first air, then the air valve is wholly or partially closed and gas only or mostly gas is admitted during a part of the stroke depending on the position of the governor and proportional to the load on the engine, and finally during the last portion of the stroke air alone. When at the end of the suction stroke the ports 'i are uncovered by the plunger d the compressed air stored in the receiver p escapes to the space in rear of the plunger and also to the cylinder a in rear of the piston b, thereby raising the pressure in those spaces and consequently increasing with the air so admitted the quantity of the charge in the cylinder a. On the inward or return stroke the valve h closes and the charge in cylinder a is compressed into the combustion chamber m, while the products of combustion in cylinder a are expelled by the piston b through the exhaust valve 0, while just before the end of the return stroke the valve his opened and the remainder of the burned gases expelled by the air which is forced from the space 11 rear of the plunger d through the valve h into the ylinder, which is thus filled with cool air at the end of the return stroke. At this stage the conditions existing in the two cylinders are the reverse of what existed at the beginning of the revolution, and in the succeeding revolution the various operations are repeated but this time in different cylinders.

' As shown in the drawings the admission valves h h and exhaust valves 0 0 are preferably placed at the top and bottom respectively of the cylinders, the latter being water jacketed.

In other respects than those herein referred to the engine may conform with ordinary practice and the various parts not specifically described may be of any suitable approved types.

1. In internal combustion engines working on the four stroke cycle, a pump cylinder in line with the working cylinder and a pump piston reciprocating in unison with the working piston, an air receiver contiguous with the pump cylinder, a port in the pump cylinder communicating with the said air receiver and traversed by the pump piston, and a passage controlled by a valve connecting the rear ends of the pump cylinder and the working cylinder, arranged substantially as herein described.

2. In internal combustion engines working on'the four stroke cycle, a pump cylinder in line with the working cylinder and a pump piston reciprocating in unison with the working piston, an air receiver contiguous with the pump cylinder, 21 port in the pump cylinder communicating with the said air receiver and traversed by the pump piston, a valve-controlled passage connecting the rear ends of the pump cylinder and the working cylinder, an

air trunk open to the atmosphere, and a non-return valve establishing communication between the said air trunk and the.air receiver, arranged substantially as described.

3. In internal combustion engines working on the four stroke cycle, a pump cylinder in line with the working cylinder and a pump piston reciprocating in unison with the working piston, an air receiver contiguous with the pump cylinder, :1 port in the pump cylinder communicating with the said air receiver and traversed by the pump piston, a valve-controlled passage connecting the rear ends of the pump cylinder and the working cylinder, an air trunk open' 'to" the-atmosphere, and non-return valves establishing communication between the said air trunk and the said air receiver and valvecontrolled passage respectively; arranged substantially as described.

4. In tandem internal combustion engines, an air cylinder interposed between and coaxial with the working cylinders, said air cylinder being closed at its forward end, a piston in said air cylinder coupled with the working pistons, meansifor admitting air to the air cylinder in front of the pistoii during its inward stroke and means for admitting airunder pressure to the said working cyl inders during the latter part of their suction stroke, substantially as described.

In tandem internal combustion engines, an air cyl inder interposed between and coaxial with the working cylinders, said air cylinder beingjclosed at itsforward end, a piston in said air cylinder coupled with the working pistons, an airvreceiver contiguous with the air cylinder, means for admitting air to the air cylinder in front of the piston during its inward stroke, means for admitting part of said air to the air receiver under pressure of the air piston during its outward stroke and means for admitting air under pressure to the said working cylinders during the latter part of their suction stroke, substantially as described.

,6. In tandem internal combustion engines, an air cylinder interposed between and coaxial with the working cylinders, said air cylinder being closed at its forward end, a piston in said air cylinder coupled with-the working pistons and arranged to compress air in the end of said air cylinder, an air receiver contiguous with the air cylinder, means for admitting a charge of air to the aircylinder in front of the piston during its' inward stroke. means for admitting part .of said charge of air to the air receiver under pressure of the air piston during its outward stroke, and means for admitting said compressed air to the respective working cylinders towards the end of their suction strokes, substantially as described.

In testimony whereof I have signed my name to this specification in the presence of two subscribing witnesses.

ARTHUR ROLLASON.

Witnesses EDWARD GARDNER, \VAL'IER J. Sknn'rnN. 

